This invention relates to medical devices and particularly to inhalers and medicated packets.
Various devices have been proposed for delivering pharmaceutical preparations to the oral cavity. An early solution was to use a propellant to discharge powdered medication into the oral cavity of the patient. This has the drawback of the use of a propellant that could be harmful to the environment and aggravate a patient's preexisting bronchial problem.
To remedy this situation, inhalation devices which rely on the inhalation of the user have been proposed. One such device is described in U.S. Pat. No. 4,846,168, entitled "Inhaler" and issued to Abiko et al. on Jul. 11, 1989. Abiko's device, while eliminating the need for a propellent, has several draw backs. First, the drug is initially contained in a capsule which is opened by the apparatus through a breaking of the capsule. This creates a risk of accidental aspiration of capsule parts. Also, the medication is subject to handling and possible contamination prior to insertion in the device. The device also lacks any means to prevent the user from blowing back into the device, such as through a cough or sneeze, and ejecting the medication.
Additionally, the device is not designed to operate between a certain minimum and maximum flow rate and therefore, the Food and Drug Administration (FDA) requirement for dose variability is hard to meet.
Another proposed inhaler is described in U.S. Pat. No. 5,042,472 entitled "Powdered Inhaler Device" and issued to Bunin on Oct. 15, 1990. This device does not use capsulized medication, but still suffers from many of the drawbacks of the previously discussed inhaler of Abiko. Specifically, it lacks any way to prevent the user from blowing into the device, it is not designed to operate in a certain optimal range of airflow and it is difficult to tell if the user has inhaled all the medication. A further draw back is that the design of the mouthpiece makes it difficult to use.
A third inhaler is described in U.S. Pat. No. 5,239,991, entitled "Disposable Powder Medicant Inhalation Device with Peel-off Cover" and issued to Chawal et al., on Aug. 31, 1993. Like the previously discussed devices, this inhaler lacks a convenient way to tell if the medicine has been fully inhaled, it does not prevent the user from blowing into the inhaler and it is not designed to operate in a certain airflow range.
Additionally, neither Bunin's nor Chawal's device are reusable. While a disposable inhaler insures a sterile dose of medication, the design is inherently wasteful.
It is clear from the foregoing, that there is a need for an inhaler and medicated packet that is easy to use, that delivers an accurate dose, and that is efficient and economical, where the powdered medication is packaged in a disposable container and the inhaler is reusable.